The effect of dihydrotestosterone (DHT) on genetically susceptible hair follicles is the cause of male pattern baldness. DHT is formed from testosterone by the action of enzyme 5 alpha reductase. Finasteride acts by blocking 5 alpha reductase and thus does not allow conversion of testosterone into dihydrotestosterone (DHT). This is the only oral medication approved by FDA.
No progression of hair loss51%
Progression of hair loss01%